WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] console hypercalls (was "How to invoke hypercalls")

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] console hypercalls (was "How to invoke hypercalls")
From: Hollis Blanchard <hollisb@xxxxxxxxxx>
Date: Mon, 14 Aug 2006 11:55:15 -0500
Cc: antoinet <xen@xxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, xen-ppc-devel <xen-ppc-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Mon, 14 Aug 2006 09:55:01 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <C1052540.64E%Keir.Fraser@xxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Organization: IBM Linux Technology Center
References: <C1052540.64E%Keir.Fraser@xxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Sun, 2006-08-13 at 18:51 +0100, Keir Fraser wrote:
> 
> The usual domU console method is to pick up a console shared page from
> start_info structure and write console data to a ring buffer embedded in
> that shared page. See Linux's driver for an example, or mini-os's.
> 
> Possibly Xen should be able to provide a serial-like interface on top of the
> console shared page, which would make initial OS porting a little easier. It
> would be something of a layer violation in the system (Xen talking up to
> dom0) but we do that already for HVM guests so there's a precedent (albeit
> one we'd like to get rid of).

This would be useful for PowerPC as well. The IBM Power Hypervisor (i.e.
the thing shipping on IBM's "System p" servers) defines the guest
console API as read/write hypercalls. It would be nice to emulate those
hypercalls so that legacy guests can run on Xen unmodified. However,
since the Xen hypervisor currently has no knowledge whatsoever of the
format of the console page, we can't.

-- 
Hollis Blanchard
IBM Linux Technology Center


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>